1. Field of the Invention
This invention relates to a lighting device for an elevator adapted to be installed in an elevator car.
2. Description of the Prior Art
In general, passengers in an elevator car often feel uneasy or stifled due to the close quarters of the car which is in fact a narrow and closed chamber. In particular, such uneasy feelings will be amplified by the discomfort of standing for a long time in an elevator installed in one of the super-multistory buildings or of travelling for a relatively long duration, or of being in an elevator car full of passengers. It is, therefore, highly desirable to improve such situations.
On the ceiling of an elevator car which has the greatest influence on the feeling of closeness of the car, however, a simple lighting device alone has hitherto been installed.
Now, the construction of such a conventional lighting device will be described with reference to FIG. 7. An elevator car 1 has a ceiling panel 2 to which a lighting panel 3 is attached. A plurality of light sources 4 such as, for example, small electric lamps, fluorescent lamps or the like are mounted on the lighting panel 3 at locations uniformly distributed thereover so that light beams emitted from the respective light sources 4 are led into the interior of the car 1 through a filter 6, such as a transparent panel filter, a half-mirror panel filter or a colored panel filter, mounted on a ceiling decorative frame 5 so as to illuminate the interior space in the car 1. In this case, the light intensity of the light sources 4 is generally determined such that a predetermined illuminance is obtained in the car 1. In other words, the light intensity of the light sources 4 is actually determined from a practical point of view such that passengers in the elevator car 1 can visually discern objects therein.
With the conventional lighting device for an elevator car as constructed in the above manner, light beams emitted from the respective light sources 4 such as small electric lamps pass through the filter 6 so that the brightness and hue of the light sources 4 are reduced. Moreover, the light beams from the light sources 4, being white light or monochromatic light and causing no change in color, are not appealing to passenger's eyes. Under these circumstances, it is desirable to develop a lighting device which can produce an illumination with color variations.
In addition, use of such light sources 4 as electric lamps employing filaments necessarily reduces the area of the light sources and therefore, for the purpose of enabling the entire area of the car ceiling to become effectively illuminated, it is necessary to employ a great number of electric lamps which are arranged in a uniformly dispersed manner over the whole ceiling surface. This results in a problem of high production costs.